James n



(No Model.)

J. N. SKINNER.

LATHE CHUCK.

No. 460,601. Patented Oct. 6, 1891.

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. UNITED STATES PATENT OFFICE.

JAMES N. SKINNER, OF NEWV BRITAIN, CONNECTICUT, ASSIGNOR' TO THE SKINNERCHUCK COMPANY, OF SAME PLACE.

LATHE-CHUCK.

SPECIFICATION forming part of Letters Patent No. 460,601, dated October6, 1891.

Application filed April 13, 1891. Serial No. 388,710. (No model.)

To all whom it may concern;

Be it known that 1, JAMES N. SKINNER, of New Britain, in the county ofHartford and State of Connecticut, have invented certain new and usefulImprovements in Lathe- Ohucks, of which the following is a full, clear,and exact descriptiomwhereby any one skilled in the art can make and usethe same.

The object of my invention is to provide a lathe-ch uck with reversiblejaws that shall be of simple construction, strong, and durable; and tothis end my invention consists in the details of the several partsmaking up the device as a whole and in their combination, as moreparticularly hereinafter described, and pointed out in the claims.

Referring to the drawings, Figure l is a detail side view of the chuck,showing two of the jaws and with two removed. Fig. 2 is a detail topview of one of the jaws. Fig. 3 is a detail perspective view of theparts composing the sectional jaw.

In the accompanyingdrawings, the letter (t denotes 'the chuck-body as awhole; I), the chuck-jaws that are usually several in number and thatare arranged in radial lines, so as to project from the face a of thechuckbody, and are also arranged in opposition to each other, so as toenable them to grasp a piece of work between their adjacent faces. Thesejaws are operated by means of radiallyarranged jaw-screws c, the headsof which project beyond the periphery of the chuckbody, so that a wrenchor like tool may be used to turn the screws and move the jaws, thethreaded portion of the screws usually passing through a nut that isformed in an integral projecting part of the jaw that lies within thechuck-body.

In order to adapt the lathe-chuck to hold different kinds of workthatis, for use with an outside or an inside grasp upon the work it isdesirable to make the jaws reversible, and several devices have beenemployed for this purpose. In each of these prior devices, however,there are disadvantages, all of which are overcome by my withinimprovement.

Each ofthe jaws'b is made up in sections d and e, the lower sectionbeing provided with the nut d, through which the j aw-screw passes, andboth sections have a roughened or serrated biting-edge on the oppositeends. The upper section 6, in order to provide for holding articles ofdifferent diameters without requiring the larger adjustment of the jawby means of the jaw-screw, is formed with a series of biting-faces e eprojecting from the upper faces of the jaw and at a distance from thefront edge Z). For taking an outside grasp or hold upon the work thefaces I), e, 1 and e are used when the jaw is faced, as shown on theright in Fig. 1 of the drawings. The same faces, so far as the uppersection 6 of the chuck-jaw is concerned, may be turned outward byreversing the upper section in regard to its position and arranging itas shown on the left in Fig. 1, in which case the grasping-faces areadapted to take an inside hold upon the piece of work.

111 order to enable the tool to be made at a comparatively smallexpense, it is desirable that the surfaces to be finished should beplane surfaces, across which straight cuts may be taken, and as thejaw-sections are made of steel and case-hardened it is desirable thatthese surfaces shall be such as can be ground to a true fit, as in thehardening the faces of the two sections become more or less dlstorted inshape. In my improved chuck-jaw the sections cl and e are formed withfiat meeting 8o surfaces, as clearly shown in Fig. 3 of the drawings. Apivot-screw f passes through the upper section and into the lower, thethreaded lower end of this screw ftaking into a threaded socket in thelower section, while the shank of the screw is left plain or does notfit any threaded socket in the upper section, but passes through it,making a snug fit, so as to enable the upper section e to be easilyrevolved upon the pivot-screw, the head of which is re- 0 cessedinacounterbored socket, so that its upper surface does not projectbeyond the outer face of the jaw when the parts are in position for use.Screws g g" pass through sockets in the upper section and extend intothreaded 5 sockets in the lower sections, these screws being arranged atopposite ends of the jaw-section and at equidistance from the axis ofthe pivot-screw. The function of these screws g g is to hold the uppersection from rotat- 10o ing on the pivot-screw, and also to serve tobind the two jaw-sections together.

In addition to these fastening means described there may be employed adetachable annular plug h, that fits into sockets h 7L2, formed directlyopposite each other in the meeting faces of the two jaw-sections (l andc, the sockets being in depth substantially equal to one-half the heightof the plug h. These sockets are formed by counterboring after thesockets for the pivot-screw f have been made. As this cylindrical plugit fits within corresponding sockets the outer walls of which areconcentric with the axis of the pivot-screw f, it serves as a supportand guide in the rotary movement of the upper section when the screws gg are removed. It also serves to strengthen the connection between thetwo jaw-sections, so that the strain of holding the piece of work thatresults largely in an endwise thrust upon the jaw-sections can be in alarge part withstood by the plug that extends into both of thejaw-sections, as described. This plug has another function as anadjusting device to take up any wear that may have come upon the plug orthe sockets by reason of this endwise thrust or strain,and this isaccomplished by rotating the plug in the sockets and presenting anunworn portion of the plug in the direction of the strain.

The upper section is made preferably to extend the whole length of thelower section and. cover it, as shown, as by this means there are noopen screw-sockets uncovered in the changed or reversed position of thejaw, and no chance, of course, for clogging such sockets. The meetingfaces of the sections being flat and there being no interengaging partsprojecting from the outer edges of the jawsections, it is only necessaryto withdraw the screws 9 g from the lower section and then simplyrevolve the upper section on the central pivot-screw and the plug andthen drive the screws 9 g into the sockets opposite to which they may beplaced. This enables the jaws of a chuck to be quickly reversed andadapted to hold any kind of work.

I claim as my invention- 1. In combination, in a lathe-chuck, asectional chuck-j aw, the two sections having flat meeting faces, apivot-screw uniting the two sections, and a removable annular plugfitting corresponding sockets arranged opposite to each other in themeeting faces of the two j aw-sections, and the fastening-screws wherebythe sections are held from turning upon the pivot-screw, allsubstantially as described.

2. In combination, in a lathe-chuck, the chuck-body and the jaw-feedingdevices, a chuck-jaw made in two sections and having flat meeting faces,the upper section extending the whole length and overlying the lowersection, the pivot-screw uniting the two sections and upon which theupper section revolves, the removable annular plug extending into asocket in each jaw-section surrounding the pivot-screw, and the screwsextending through opposite ends of the upper section, whereby it is heldagainst rotary movement on the lower section, all substantially asdescribed.

JAMES N. SKINNER.

Witnesses:

E. J. SKINNER, A. B. JENKINS.

